Abstract: A positive-displacement fluid flow measuring system, especially for hydrocarbon fuel dispensers. The measuring system comprises, in addition to a positive-displacement meter per se, a correction system for correcting the loss of head in the meter. The correction system comprises a differential pressure detector responsive to the difference between the pressures at the inlet and the outlet of the meter. The displacement of the membrane enables an external motor to be coupled to the shaft of the meter by means of the plates.

Abstract: A system that provides assistance in opening the main valve in a hydrocarbon dispenser nozzle. The external control member for opening the main valve acts on a pilot valve of small flow section, with the main valve being opened by fluid pressure applied to it as a result of the pilot valve being opened. The seat of the pilot valve is formed in the main valve member.

Abstract: An aerodynamic enclosure is placed in the flow, the enclosure including an opening enabling the enclosure to be filled with the flowing fluid, and having a thermal pulse generator mounted flush with its wall, which generator is suitable for emitting modulated thermal pulses simultaneously to the outside and to the inside of the enclosure. A first thermal sensor is located in the flow and a second thermal sensor is located in the enclosure. The sensors measure propagation times or phase shifts of the thermal waves respectively in the flow and in the non-flowing fluid, thereby making it possible to deduce the value of the fluid flow rate while compensating for any variations in the temperature, pressure, and composition of the fluid. The invention is applicable to gas metering.

Abstract: The flow rate sensor is made from a silicon substrate (1). A first face (A) of the substrate is provided with a heating element (2) disposed in a first region (R1) and with at least one thermometer component (4) disposed in a second region (R2), the first and second regions being insulated from each other by a third zone (R3) of oxidized porous silicon. According to the invention, the sensor is adapted to receive the flow of fluid (E) over the second face (B) of the substrate (1), with the first and second regions (R1, R2) forming respective thermal short circuits between the first and second faces (A, B) of said substrate.

Abstract: A flow rectifier for mounting in a circular section duct conveying a fluid flow, the rectifier establishing two series of oppositely-rotating vortices in a ring, which vortices cancel one another, and are created by two series of angularly offset fins. The first series of fins is disposed uniformly around the inside surface of the ring while the second series of fins is disposed uniformly around a circumference centered on the center of the ring.

Abstract: An emulator which is able to operate on a standard single phase 120 VAC line, generates simulated three-phase alternating current in order to demonstrate the operation of a polyphase electricity meter. The emulator is also capable of demonstrating the operation of the polyphase electricity meter which has been incorrectly wired into the polyphase circuit, i.e., with incorrect or missing connections to the current transformers; or in which there are problems with the phasing of the polyphase circuit, i.e., incorrect phase differences between circuits or between the currents and voltages within any of the phases.

Abstract: A method and system is disclosed for indication and prevention of tampering with an electricity meter having control circuitry for automatic remote reading. The control circuitry, provided externally of the meter in a base or base extension, to which the meter is connected, is also used for tamper detection. Embodiments of the invention include use of optical sensing, voltage detection and proximity detection. Ambient light sensing may be performed to detect separation of the meter from the external receptacle. Reflected light to a reflective surface of the meter is sensed to determine if the meter is properly engaged. Presence of a meter connection plug element may be sensed either optically or by position responsive switch. Voltage of the utility supply and meter user output may be monitored to determine tampering.

Abstract: A distributed temperature sensor comprises an elongate ultrasonic waveguide having a number of zones along its length, each zone having a grating formed on it. This is typically achieved by incorporating uniformly spaced notches or bands (or collars) throughout the zone. The grating spacing in each zone is different, so that each grating reflects a characteristic frequency. This frequency varies as the temperature of the zone varies, so if wide-band ultrasonic pulses are launched into the waveguide, the temperature of each zone can be determined from the reflected frequencies.

Abstract: The invention relates to a method and to apparatus for quickly and accurately positioning the rotary magnetic heads of a recorder/reader unit. The support for the magnetic heads includes a turntable and a countertable that are circular and that have a common axis of rotation, each including a peripheral support zone and a central support zone. The magnetic heads are situated around the periphery of the turntable. A screw enables the peripheral support zones to be brought into contact with each other and then the central support surfaces to be brought into contact with each other. The invention is applicable to recording and/or reading information on a magnetic tape.

Abstract: An optical sensor for monitoring position of a movable object comprising a LED and a phototransistor is provided with control circuitry, which is responsive to an output signal generated by the phototransistor for causing the LED to suspend radiation of light. When the light reflected from a reflective area of the object falls on the phototransistor, the control circuitry turns off the LED as soon as the output of the phototransistor goes below a threshold level signifying that the phototransistor has been turned on. When the light is absorbed by a non-reflective area of the object and the phototransistor is not turned on, the control circuitry turns off the LED after a predetermined time period, which is chosen to be slightly larger than the response time of the phototransistor.

Abstract: The invention relates to sensors having field effect semiconductors. The sensor of the invention comprises a ring oscillator constituted by an odd number of CMOS inverters disposed in a zone sensitive to the physical property to be measured. In order to increase the sensitivity of the sensor, the N channel of the NMOS transistor in each CMOS inverter is disposed perpendicularly to the P channel of the PMOS transistor.

Abstract: An electrical measuring device utilizing a shunt, an electronic measuring circuit floating at the potential of the shunt and a first voltage divider connected between the shunt and a neutral point to provide a first voltage signal to the circuit. To obtain the benefit of decoupling the potential between the shunt and the intermediate point of the first voltage divider, the device includes an additional terminal connected to the shunt by a second voltage divider, whose intermediate point supplies a second voltage signal used differentially with the first.

Abstract: A self-actuating throttle valve for use with fluid measurement apparatus such as a water meter. The valve includes a cylindrical body disposed within the outlet of the fluid measuring apparatus, fluid bypass openings formed in the body to enable fluid to flow through the body, and a piston disposed within the body. The piston is biased by a spring in a first position whereby the fluid may flow around the piston and body and through the bypass openings when the rate of fluid flow is below a predetermined amount. When the rate of fluid flow is above a predetermined amount, pressure from the fluid causes the piston to move to a second position whereby the piston covers the bypass openings by a predetermined amount to substantially reduce fluid flow. The throttle valve prevents damage to the fluid measurement apparatus when high fluid flow rates are encountered. The valve has particular application in the area of fire service water metering devices which include both a high flow rate measurement device (e.g.

Abstract: A dry (unpressurized) hydrant utilizes a hydrant pipe formed from PVC. One end engages a sliding swivel mount attached to a post with the other end of the pipe being free to swing and to be placed within a nearby body of water. The free end may include a strainer assembly, also formed of a PVC material. The strainer end may be placed at a predetermined depth within a body of water, such as a lake, pond or the like, by means of a second support located proximate the body of water. Alternatively, the strainer end of the hydrant pipe may be provided with a buoyant float to maintain the level of the strainer end of the hydrant pipe just below the water surface. In another embodiment, the strainer end of the hydrant pipe is provided with a rotating wheel assembly which enables the strainer end of the hydrant pipe to be rolled into position beneath the surface of the body of water. The dry hydrant is formed from inexpensive and lightweight materials and can be stored dry when not in use.

Abstract: An improved drive shaft for a positive displacement type water meter includes a flexible spring arm formed on one end of the shaft for engaging the drive spindle of a nutating disk measuring element disposed within a water meter. The other end of the drive shaft is connected to a magnetic drive which, in turn, is magnetically coupled to a conventional mechanical register. Under normal conditions, the nutating disk measuring element and drive spindle oscillate in the water meter at a rate proportional to water meter flow. The drive spindle engages the spring arm of the drive shaft causing the drive shaft and magnet to rotate. The magnet is coupled through the water meter casing to a second magnet in the register. Rotation of the second magnet is used to drive the mechanical register to register water consumption. In the event the first magnet within the meter casing becomes frozen to the casing because of external freezing conditions, the drive spindle will snap past the flexible spring arm.

Abstract: The invention relates to a device for encoding and remotely transmitting information concerning the position and the direction of rotation of a rotary element. This device comprises an encoder driven by sensors suitable for producing an analog signal whose amplitude varies on each change of state of each sensor by an amount that depends on which sensor changes state. The invention is applicable to electricity meters.

Abstract: A two wire/three wire utility data communications system for remotely reading utility meter registers. In the two wire version, a hand-held reading unit is inductively coupled over two wires via a port located remotely from a meter register. Alternatively, a meter interface unit (MIU) may be connected directly to the register via three wires. Each register includes one or more wheel position encoders. An AC interrogation signal is applied by the reading unit to encoder circuitry at the meter which powers the circuitry and causes the position of each encoder wheel to be read. In the two wire mode, register display information (e.g. the current meter reading) is transmitted back to the reading unit by varying the load (impedance) presented by the register side of the circuit. This causes a corresponding variation of the amount of current drawn from the reading unit. The current-modulated signal is decoded by the reading unit and converted into a register reading.

Abstract: A water level measurement system for use with a pressurized power plant boiler comprises a tubular pressure vessel for attachment to one end of the boiler such that the water level in the pressure vessel is the same as in the boiler. The pressure vessel has a central rod-like conductor which together with the vessel forms a coaxial RF waveguide. A pair of spaced reference discontinuities are provided in the conductor above the maximum level of the water, so that an RF pulse injected into the waveguide is reflected successively by both discontinuities and the surface of the water. The level of the water can then be determined independently of changes in the dielectric constant of the vapor above it, from the ratio between the time intervals between the first and second reflected pulses and between the first and third reflected pulses. The conductor is mounted at the top of the pressure vessel by way of a pressure seal and a ceramic insulator.